Lathe for forming a virtually cylindric surface on an article



mvs n'roizs Walter P. Lcskey 2 Sheets-Sheet Merle Bibb BY Roger M.Shermon W P LASKEY ETAL LATHE FOR FORMING A VIRTUALLY CYLINDRIC SURFACE ON AN ARTICLE Filed March 5, 1963 Aug. 17, 1965 Aug. 7, 1965 w. P. LASKEY ETAL 3,200,681

LATHE FOR FORMING A VIRTUALLY CYLINDRIC SURFACE ON AN ARTICLE Filad larch 5, 1963 2 Sheets-Sheet 2 INVENTORS Walter P. Leakey Merle Blbb Roqar M. Sherman smas er LATHE FOR FORMING A- VIRTUALLY CYLINDRIC SURFACE ON AN ARTICLE Walter P. Laskey, Hayward, and Merle Bihb and Roger M. Sherman, Palo Alto, Calif., assignors to The Kor-It Company, inc Santa Clara, Calif., a corporation of California Filed Mar. 5, 1%3, Ser. No. 263,090 8 Claims. ((Jl. 82-42) This invention relates to a lathe for forming an approximately cylindric surface .on an article and more particularly to a simplified cutting tool holder for such lathe.

The specific embodiment of the present invention de scribed in detail hereinafter concerns a machine for finishing or trueing up the running surface of a roller skate wheel. However, the present invention is not to be considered as limited to such device.

The specific embodimentdescn'bed in detail hereinbelow comprises a motor for rotatively driving the skate Wheel about its central axis. A cutting tool for finishing the surface of the skate wheel is mounted on a piovtal arm to afford arcuate movement of the cutting tool across the surface of the wheel. The arm is mounted at a point remote from the cutting tool to permit pivotal movement about an axis perpendicular to the axis of wheel rotation, and is adjustably slidable along the axis of pivotal movement to eifect movement of the cutting tool toward and away from the article surface. A hydraulic actuator having a piston slidable in a cylinder is provided for controlling the rate of pivotal arm movement. A connecting rod links the piston to the pivotal arm. The hydraulic actuator includes a spring or the like for urging the piston toward one end of the cylinderand a fluid conduit communicating with the opposite end -of the cylinder. Hydraulic fluid in the conduit flowsin response to movement of the piston in the cylinder, and a valve for restricting the flow of fluid in the conduit in one direction affords control of the rate ofm'ovement of the piston in the cylinder which in turn controls the rate of movement of the cutting tool across the surface of thearticle.

' Because of the high cost of quality roller skate wheels, the surfaces of such wheels are periodically refinished when the surface of the wheel becomes worn, roughened or out of-round. Such refinishing is typically done at roller skating rinks where the skates are used. Heretofore, such refinishing has been performed by the use of abrasive grinding wheels since it is impractical to provide a conventional lathe in each rink. Skate wheel finishing by the grinding method has the disadvantage that the quality of the finish on the skate wheel is affected by the smoothness and shape of the grinding wheel. To assure a wheel must be frequently dressed, an expensive and timeconsuming operation. Furthermore grinding invariably creates a dust condition. Roller skate wheels can, of course, be turned on a conventional lathe. This technique of finishing the wheel, however, has the disadvantage of high cost and of requiring an operator with considerable skill using an expensive machine. 7

Therefore it is an object of this invention to provide a lathe for finishing roller skate wheels that is inexpensive, simple and rapid in operation, and provides an acceptable, virtually cylindric surface finish.

Another object is to provide a lathe for finishing roller skate wheels that can be operated by personnel without any special training. This object is important in that skaters normally desire to have their skate wheels refinished at a roller skating rink, a place whereit is not economically feasible to retain highly trained personnel. I The simplicity of operation arises in part from the fact that good finish on the skate Wheel, the abrasive grinding .by his customers.

' 3,2fififi8l Patented Aug. 17, 1965 the rate of cutting tool movement across the surface of the skate wheel is. controlled independently of operator attention.

Still another object is to provide a wheel trueing device which virtually eliminates dust during the trueing operation.

Yet another object is to provide a skate wheel'finishing device of simple construction and low cost. In machines of this type low cost is essential since each roller skating rink proprietor desires to have facilities on the prem1ses for servicing both his own skates and those skates owned The expense of conventional lathes renders them unsuitable for such wide application. The present invention secures extreme simplicity by providing a pivotally mounted tool holder rather than the conventional tool holder that is moved along a highly finished bed by'expensive leading devices. A cutting tool supporting pivot arm of sufficient length provides a virtually cylindric surface which appears as atrue cylinder on visual inspection, a standard adequate for the intended purpose.

These and other objects will be-more apparent after referring to the following specification and attached drawings in which:

FIGURE 1 is a side elevation view of the invention in partial cross section and showing portions of the apparatus in schematic form;

FIGURE Z is an end view taken substantially along line 22 of FIGURE 1;

FIGURE 3 is a detailed view of a skate wheel mounting chuck used in practicing the present invention.

Referring more particularly to the drawings, reference numeral 12 indicates a conventional electric motor or the like having a shaft 14 on'which i mounted a chuck 16 for supporting a centrally apertured skate wheel W for rotation about its central axis. Motor 12 is provided with an on-oif switch 18 for selectively energizing the motor, and is mounted on a top plate 20 of a base designated generally as 22. Base 22 is formed in a generally inthrough which arm 38 extends; an adjustable stop 42 is' provided on the top of plate 20 to limit pivotal movement of arm 38 toward motor 12. Remote from shaft 36, arm 38 has mounted thereon a cutting tool 43 which is held securely in place by a set screw 44. The cutting edge of cutting tool .43 is formed in a conventional manner for finishing the surface of skate wheel W as the tool is moved across the surface of the wheel.

Shaft 36 has a threaded portion 46 at an end thereof exterior side plate 26. A member 48 formed with a threaded opening 50 is provided for threadably engaging threaded shaft portion 46. Member 48 bears against the exterior surface of side plate 26, therefore rotation of 'member 48 moves shaft 36 along its longitudinal axis.

Such movement in turn moves arm 38 as a consequence of which cutting tool 43 may be positioned relative the surface of skate wheel W. A compression spring 52 circumscribes shaft 36 and tends to bias arm 38 away from side wall 26. It will be seen that adjustment of cutting tool 43 toward and away from the surface of skate wheel W is effected by rotation of member 48 since side wall 26 against which member 48 bears is fixed relative to the axis of rotation of the skate wheel.

Chuck 16 is provided with a conical portion 54 from the center of which extends a mandrel 56 having on the outer extremity thereof a threaded portion 58 for receiving a nut 60 or the like. A plurality of conical portions 54 and mandrels 56 can be provided to accommodate different sized Wheels, and can be rapidly interchanged by loosening a set screw 62 which retains the conical portion and the mandrel in the chuck. Chuck 16 is provided with a bore 64 that is coaxial with mandrel 56 and with set screws 66, which are adapted to secure the chuck to motor shaft 14.

In operation a skate wheel is inserted onto mandrel 56 and secured thereto by nut 60. Conical portion 54 serves to properly center the skate wheel relative the axis of mandrel 56 and motor shaft 14. With arm 38 in the position shown in solid lines in FIGURE 1, the motor 12 is energized by operating switch 18. When skate wheel W reaches full rotative speed, arm 38 is moved in a clockwise direction as viewed in FIGURE 1 to move cutting tool 43 in an .arcuate path across the surface of skate wheel W. As will be appreciated by those skilled in the art, if the arm 38 is moved rapidly a relatively rough cut will be made on the surface of the wheel, whereas a slower movement of the arm will cause a smoother finish to be obtained. If it is desired to move cutting tool 43 toward the surface of skate wheel W, member 48 is rotated in the appropriate direction to draw shaft 36 toward the right as viewed in FIGURE 2. This action moves arm 38 and cutting tool 43 toward the surface of skate wheel W, and another cut may be taken by pivoting arm 38 back and forth.

Of course the surface formed on skate wheel W by this method will be slightly concave, at least from a purely mathematical viewpoint. However, it has been found that if the axis of shaft 36 is spaced from the surface of skate wheel W by a distance suflicient to cause arm 38 to subtend an angle of less than about 14 degrees when moving the cutting tool 43 from one edge of skate wheel W to the opposite edge, a virtually cylindric surface is formed on the skate wheel. Such surface will appear cylindrical upon close visual inspection of the Wheel.

As mentioned herein above, the smoothness of the finish on the surface of skate wheel W, is affected by the speed with which the cutting tool traverses the surface of the wheel in response to pivotal movement of arm 38. Means are provided for controlling this rate of movement to permit unskilled operators to attain smooth finishes with the equipment.

A connecting rod 68 is provided and is pivotally attached at one end thereof to shaft 38 by a clevis joint 76. The opposite end of connecting rod 68 is connected to a piston 72 that is adapted for sliding movement with a cylinder 74 of a hydraulic actuator 76. Hydraulic actuator 76 is pivotally mounted to end plate 28 by means of a clevis joint 78. Within hydraulic actuator 76 and circumscribing connecting rod 68 is a compression spring 80 which urges piston 72 toward the left as viewed in FIGURE 1 which in turn urges arm 38 against adjustable stop 42. Communicating with the end of cylinder 74 opposite that in which spring 80 resides there is a conduit 82 connected to a hydraulic flow control unit 84. Hydraulic fluid control unit 84 includes a conventional valve 86 in a branch conduit 82a which valve is adapted to provide variable impedance to the flow of hydraulic fluid therethrough. The rate at which hydraulic fluid flows through valve 86 is varied by adjustment of a control knob 88 operatively connected to valve 86 through suitable linkage. A conduit 82b is provided for conveying the hydraulic fluid from valve 86 to a fluid reservoir 90. Hydraulic fluid from reservoir 90 returns to conduit 32 through a branch conduit 8-20 which has interposed therein a conventional check valve 92 for permitting passage of hydraulic fluid therethrough in only one direction.

The apparatus for automatically controllingthe movement of arm 38 operates as follows. With arm 38 in the position shown in solid lines of FIGURE 1, that is, pivoted fully counterclockwise as viewed in the figure, a skate wheel W is mounted in chuck 16 as described above. Arm 38 is then manually pivoted in a clockwise direction or toward the right as viewed in FIGURE 1. Such action of course moves cutting tool 43 across the surface of the wheel. Because rate of movement in this direction is unimpeded the arm can be moved rapidly to effect a relatively rough cut. Furthermore, piston 72 is moved within cylinder 74 toward the right, as a consequence of which hydraulic fluid is drawn into the cylinder from reservoir 90 through check valve 92, conduit branch 82c and conduit 82. Concurrent with the movement of hydraulic fluid energy is stored in spring by compression thereof. When arm 38 is moved to the position shown by broken lines in FIGURE 1, release of the arm will cause it to move back to the left in a counter-clockwise direction because the pressure stored in spring 80 acts against piston 72 and through connecting rod 68 to so move the arm. The counter-clockwise pivotal movement ceases when arm 38 meets adjustable stop 42. The rate of such return movement, however, is limited by the flow of hydraulic fluid through conduit 82, branch 82a and control valve 86 since the control valve impedes the flow of hydraulic fluid thereto. The rate of movement can be adjusted by a movement of adjusting knob 88. The control of piston rate of movement just described of course controls the rate of movement of cutting tool 43 across the surface of skate wheel W. As will be appreciated by those skilled in the art, the slower the rate of movement of the tool across the surface of the wheel, the smoother the finish provided on skate wheel W. Each time that arm 38- is pivoted cutting tool 43 can be drawn closer to the surface of skate wheel W by rotation of member 48 in the manner described hereinabove.

Although the invention has been illustrated in terms of a roller skate wheel finishing lathe, it may be practiced in finishing the surface of any article that requires only a virtually cylindric surface. The wider the article, the longer arm 38 must be made to assure that the angular movement of the arm from one edge of the article to the opposite edge is less than 14 degrees.

While one embodiment of the invention has been shown and described, it will be obvious that other adaptations and modifications may be made without departing from the true spirit and scope of the invention.

We claim:

1. A lathe for forming a virtually cylindric surface on an article between two ends of the article spaced from one another along a central axis of the article comprising: means for rotatably driving the article about the central axis thereof, a cutting tool having a cutting edge narrow with respect to the space between the article ends and being formed for finishing the surface of the article, means for mounting said cutting tool for movement across the surface of the article, said tool mounting means being adapted for pivotal movement relative an axis, last said axis being fixedly disposed perpendicular to the axis of rotation of said article and spaced therefrom a distance sufficient that movement of said cutting tool across said article surface forms a virtually cylindric surface, and stop means for limiting pivotal movement of said tool mounting means.

2. The invention according to claim 1 in combination with means for adjustably positioning said tool mounting means along said pivotal axis to effect movement of said cutting tool toward and away from the surface of the article.

3. A lathe for forming a virtually cylindric surface on an article between two ends spaced apart along a central axis of the article comprising means for rotatably driving said article about the central axis thereof, a cutting tool having a cutting edge narrow with respect to the space between the article ends and being formed for finishing the surface of the article, means for mounting said cutting tool for arcuate movement across the surface of said article between the ends thereof, said cutazoaesr ting tool mounting means being adapted for pivotal movement relative an axis perpendicular to the axis of rotattion of said article, said pivotal axis being fixedly spaced from the surface of the article sothat the arc subtended by said mounting means during pivotal movement there of in moving said cutting tool from one end of the article to the other end thereof is less than'fourteen degrees, stop means for limiting pivotal movement of said cutting tool mounting means, and means for adjustably positioning said cutting tool mounting means along the axis of arcuate movement thereof to afford movement of said cutting tool toward and away from the article surface.

4. A lathe for forming an approximately cylindric surface on an article between two ends of the article spaced apart along a central axis of the article comprising, means for rotatably driving said article about the central axis thereof, a cutting tool having a cutting edge narrow with respect to the space between the article ends and being formed for finishing the surface of the article, an arm having means for mounting said cutting tool thereon, means for mounting said arm at a point remote from said cutting tool mounting means for pivotal movement about an axis, said pivotal axis being perpendicular to the axis of rotation of said article and being fixedly spaced from said tool mounting means by a distance at least sufficient to provide a visually cylindric surface'of said article when said cutting tool is moved across the article surface, and stop means for limiting pivotal movement of said arm.

5. A lathe for forming a virtually cylindric surface on an article between two ends of the article spaced from one another along a central axis of the article comprising an arm mounted for pivotal movement about an axis, a cutting tool for finishing the surface of said article, said cutting tool being secured to said arm remote from said axis of pivotal movement, means for rotatably driving the article about the central axis thereof, said axis of article rotation being disposed perpendicularly relative the axis of pivotal arm movement, said axis of article rotation being fixedly spaced from said axis of pivotal arm movement so that the arc subtended by said arm during pivotal movement thereof in moving said cutting tool from one end of the article to the other end thereof is less than fourteen degrees, means for adjustably positioning said arm along the axis of pivotal movement to afford movement of said tool toward and away from the surface of the article, means for pivotally moving said arm in at least one direction at a controlled rate, and stop means for limiting pivotal movementof said arm.

6. The invention according to claim 5 wherein said arm moving means comprises a connecting rod having a'first and second end, means for pivotally attaching said first end to said arm, a hydraulic actuator including a cylinder and a piston slidable therein, said second connecting rod end being attached to said piston, means for urging said piston toward one end of said cylinder, means forming a conduit in communication with the opposite end of said cylinder, noncompressible fiuid in said conduit fiowable in response to movement of said piston in said cylinder, and means for controllably impeding fluidflow in said conduit when said piston is moved in a direction caused by said pistonurging means and for affording unrestricted flow in said conduit when said piston is moved against said piston urging means.

7. The invention according to claim 5 wherein said arm positioning means comprises a shaft rotatably and slidably journalled coaxially with the arm pivotal axis, said arm being fixedly attached to said shaft, a threaded portion formed on said shaft, means forming a threaded opening for threadably engaging said shaft, and means fixing said opening forming means relative the axis of article rotation for effecting movement of said cutting tool toward and away from said article surface in response to rotation of said threaded opening forming means.

8. A lathe for forming a virtually cylindric surface on a centrally apertured roller skate Wheel comprising a chuck receivable in said aperture for securing said wheel thereto, a motor for rotatably driving said chuck about an axis, a base for supporting said motor, a shaft, means for supporting said shaft for rotative slidable movement on said base, an arm fixedly attached to said shaft and extending substantially radially therefrom, said arm being adapted to move proximate the surface of said wheel in a plane parallel to the axis of chuck rotation about the axis of rotative movement of said shaft, a cutting tool afiixed to said arm at a point proximate said wheel for movement across the surface of said wheel in response to pivotal movement of said arm about the axis of said shaft, said cutting tool being spaced from said shaft axis by a sufiicient distance that said arm in moving said cutting tool across the skate wheel surface subtends an arc of less than fourteen degrees, means for slidably positioning said shaft to afford movement of said cutting tool toward and away from the skate wheel surface, a connecting rod having a first end and a second end, means pivotally mounting said first end on said arm intermediate said cutting tool and said shaft, a hydraulic actuator including a cylinder and a piston slidable therein, said second rod end being alfixed to said piston, means for urging said piston toward one end of said cylinder, means forming a conduit in communication with the opposite end of said cylinder, a noncompressible fluid in said conduit flowable in response to movement of said piston in said cylinder, and means for controllably impeding fluid flow in said conduit when said piston is moved in a direction caused by said. piston urging means and for affording unrestricted flow in said conduit when said piston is moved against said piston urging means.

References Cited by the Examiner UNITED STATES PATENTS 577,332 2/97 Fangye et a1. 82--l1 X 754,548 3/04 Dietz 142-36 1,663,192 3/28 Compton 8212 3,120,723 2/64 Jessup 82--11 X WILLIAM W. DYER 1a., Primary Examiner. i 

1. A LATHE FOR FORMING A VIRTUALLY CYLINDRIC SURFACE ON AN ARTICLE BETWEEN TWO ENDS OF THE ARTICLE SPACED FROM ONE ANOTHER ALONG A CENTRAL AXIS OF THE ARTICLE COMPRISING: MEANS FOR ROTATABLY DRIVING THE ARTICLE ABOUT THE CENTRAL AXIS THEREOF, A CUTTING TOOL HAVING A CUTTING EDGE NARROW WITH RESPECT TO THE SPACE BETWEEN THE ARTICLE ENDS AND BEING FORMED FOR FINSIHING THE SURFACE OF THE ARTICLE, MEANS FOR MOUNTING SAID CUTTING TOOL FOR MOVEMENT ACROSS THE SURFACE OF THE ARTICLE, SAID TOOL MOUNTING MEANS BEING ADAPTED FOR PIVOTAL MOVEMENT RELATIVE AN AXIS, LAST SAID AXIS BEING FIXEDLY DISPOSED PERPENDICULAR TO THE AXIS OF ROTATION OF SAID ARTICLE AND SPACED THEREFROM A DISSTANCE SUFFICIENT THAT MOVEMENT OF SAID CUTTING TOOL ACROSS SAID ARTICLE SURFACE FORMS A VIRTUALLY CYLINDRIC SURFACE, AND TOP MEANS FOR LIMITING PIVOTAL MOVEMENT OF SAID TOOL MOUNTING MEANS. 